Normally, fusion is not possible because the strongly repulsive electrostatic forces between the positively charged nuclei prevent them from getting close enough together to collide and for fusion to occur. Hydrogen, heated to very high temperatures changes from a gas to a plasma in which the negatively-charged electrons are separated from the positively-charged atomic nuclei (ions). But the cost and complexity of the devices involved increased to the point where international co-operation was the only way forward. The Fusion Industry Association report The Global Fusion Industry in 2022 said that $2.83 billion of new investment was declared by private nuclear fusion companies since the 2021 edition of the report.įusion powers the Sun and stars as hydrogen atoms fuse together to form helium, and matter is converted into energy. Following a breakthrough at the Soviet tokamak, fusion research became 'big science' in the 1970s. Initially, fusion research in the USA and USSR was linked to atomic weapons development, and it remained classified until the 1958 Atoms for Peace conference in Geneva. Today, many countries take part in fusion research to some extent, led by the European Union, the USA, Russia and Japan, with vigorous programmes also under way in China, Brazil, Canada, and Korea. The main hope is centred on tokamak reactors and stellarators which confine a deuterium-tritium plasma magnetically.The fundamental challenge is to achieve a rate of heat emitted by a fusion plasma that exceeds the rate of energy injected into the plasma.Fusion power offers the prospect of an almost inexhaustible source of energy for future generations, but it also presents so far unresolved engineering challenges.

Nuclear fission and fusion